A filament-type vegetation trimmer of the electrically powered type such as described in German utility models Nos. 6,919,841 and 6,938,265 has a long handle from the rear end of which extends the power cord and on the front end of which is mounted an electric motor. A head carried on the output shaft of this motor houses a spool supply of a monofilament line whose end extends out of the head. As the head is rotated at high speed, the whirling line end can cut through light vegetation. Such a trimmer is relatively easy and safe to use, as the line cannot seriously damage either the user or anything substantial adjacent the area being trimmed.
During use the line end periodically breaks off. It therefore becomes necessary for the user to extend a new section of line. This can be done in a standard type of system by bumping the supply-carrying head on the ground to release a section of line from a spool carried in the head. It is also possible on some of the more sophisticated systems to electrically actuate a solenoid clip that releases a section of line.
A problem with such machines is that frequently the end piece of the line breaks off, so that the cutting radius of the machine decreases, without the user noticing it. Only when the efficiency of the device drops off drastically does the user notice and extend a new line section. This necessity of keeping an eye out to constantly check on the condition of the cutting line has been found to be more than a minor inconvenience.